Amplifier and communication apparatus

Abstract

A wideband amplifier that exhibits an even amplification characteristic in a wide frequency range, prevents degradation from occurring due to a parasitic capacitance, and that exhibits a shortened group delay time. The wideband amplifier includes, as a load of a current output amplifying element, a parallel combination of bandpass filters comprising L-C parallel and L-C-R series resonance circuits. The bandpass filters each have a plurality of poles and have zeros therebetween in the s-plane and provide an improved even characteristic in a respective pass band. The output terminal of the amplifying element serves as the output terminal of the amplifier, resulting in no problem of group delay. The capacitive elements between the output terminal of the amplifier and the GND assimilate, as parts of their constants, the parasitic capacitance, thereby preventing degradation of the frequency characteristic.

Description

technical field [0001] The present invention relates to amplifiers and communication devices for transmission and reception during wireless communication, especially amplifiers and communication devices that are applied to, for example, UWB (Ultra Wide Band) communication and that perform voltage amplification on high frequency components of received signals. [0002] More particularly, the present invention relates to an amplifier and a communication device that jointly perform an amplification operation in a wide frequency bandwidth used in UWB communication, and particularly have flat amplification characteristics over a wide frequency bandwidth, thereby being able to prevent degradation caused by parasitic capacitance ( degration) and broadband amplifiers and communication devices with very short group delays. Background technique [0003] Wireless LANs are attracting increasing attention as systems that can free users from LAN wiring required by wired methods. Accordin...

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Problems solved by technology

[0019] (2) if Figure 8 As shown, the amplifier has a relatively simple structure; however, a broadband amplifier has a group delay

[0031] (2) In the case where a post-stage circuit such as a down-converter, AGC, or A / D converter is connected to the output terminal 108 of the amplifier, this circuit will act as a parasitic capacitance of the amplifier, but since the output terminal of the amplifier is connected to There is no capacitive part between GND, therefore, the parasitic capacitance added to the output cannot be absorbed as a part of the constant, and the frequency characteristic will be degraded

[0032] exist Figure 12 In the example shown, since the amplifier is constructed such that the series capacitance Cs106 and the parasitic capacitance are in series, it is difficult to eliminate the effect of the parasitic capacitance

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